vacume problem on 95 GM?

My mech said reason for a/c cutting in and out has to do with vacume deficiency. He said prob could be behind dash or behind pass side front fender. Anyone have any history with that?

Do a Google ''youtube auto smoke machine''

Do you have the Electronic Air Temperature Control (EATC) unit? If so, the vacuum solenoid o-rings are probably dried out and need to be replaced. When vacuum is insufficient, it will default to the defroster position.

Thanks for the replies. Your right, it does revert to the defrost position. Where would the "EATC" be if I do have it? Sorry to sound so ignorant!!!!! Btw,could a vacume deficiancy cause spongy brakes?

If you have a vacuum leak significant enough to affect brakes, the brakes would become hard, not spongy. And he engine would likely run like crap.

An you have an EATC, you will have the digital thermostat controls. The one where you set the temperature you desire and it can control everything for you. If you do not have the EATC, you have three knobs instead - temperature, blower speed, and where you want your air coming from.

Here's an abundance of information about the EATC and some pictures comparing the EATC and manual controls.

http://p71interceptor.com/eatcswap/

Thanks for the info. No I guess I don't have the EATC.